The invention is directed to a process for patterning non-photoimagable ceramic tape utilizing photoresist technology wherein the photoresist, after imagewise exposure and development, acts as a development mask for the ceramic tape.
Ceramic green tapes have long been used as dielectric substrates in hybrid circuit fabrication and are now being used in an emerging technology of flat panel display development. Forming via holes or barrier rib patterns on the tape is currently done by mechanical processes such as die punching or sandblasting. However, as the industry trend moves toward finer feature sizes and more complicated patterns, mechanical patterning processes fall short in meeting this trend.
Photoimaging can satisfy such requirements on resolution and pattern complexity. However, the conventional photoimagable ceramic tape has two major drawbacks: (1) physical hardening of the tape as a result of photocrosslinking or polymerization tends to make the tape brittle and therefore difficult to handle, and (2) reflective scattering of light by material interfaces causing partial crosslinking of tape under dark silver halide patterned areas like via holes which reduces space resolution.
The object of this invention is to solve the above-noted problems by providing a new method of patterning a ceramic green tape without the ceramic tape itself containing photoimagable components.
The invention is directed to method for patterning non-photoimagable ceramic tape comprising the steps of:
(a) applying to a non-photoimagable ceramic tape that contains at least one polymeric binder containing acid functional pendant groups at least one photoresist comprising a photosensitive layer and at least one polymeric binder containing alkaline functional pendant groups;
(b) exposing the photoresist wherein exposed sections of the photoresist become hardened;
(c) removing sections of the photoresist that were not hardened with a first developer containing an acidic developing solution revealing sections of the ceramic tape; and
(d) removing the revealed sections of ceramic tape with a second developer containing an alkaline developing solution.
The invention is further directed to a process with chemistries opposite of that given above.